1. Field of the Invention
This invention relates to flow conditioners and flow meters. More specifically, the invention is a flow plug whose holes exhibit a length-to-size uniformity.
2. Description of the Related Art
There are numerous applications utilizing fluid flow in a conduit where a flow must be conditioned or one or more process variables associated with a fluid flow (e.g., pressure, temperature, mass flow, etc.) must be measured. “Flow conditioners” include simple orifice plates. To measure a variety of flow process variables, a variety of “flow meters” have been developed. Flow meters having no moving parts or power requirements are preferred.
Some flow meters include an orifice plate disposed in a fluid flow. The orifice plate (i.e., a plate with multiple holes passing therethrough) is typically used to condition a flow before and/or after flow measurement instrumentation.
However, this often requires some type of disruption of the flow where the flow measurement instrumentation (e.g., pitot tubes, spinning fans, etc.) is positioned. Furthermore, multi-hole orifice plates of varying hole placement and size can have a high coefficient of discharge. However, in such cases, permanent pressure loss varies widely depending on the pattern of holes. Furthermore, multi-hole orifice plates can produce multiple vena contracta (i.e., downstream location from a flow restrictor where the flow jet area is smallest, flow velocity is largest, and pressure is smallest). These conditions yield permanent pressure losses and yield less than optimal confidence in the flow measurement results generated by such flow meters.